Reply to rebuttal: Gene variants of the cytochrome P450 CYP2C9 affect oral anticoagulation with warfarin.
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Biomedical subjects
Publications and source records attributed to V Brancaccio.
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The prevalence and pathogenesis of portal vein thrombosis (PVT) in patients with cirrhosis without hepatocellular carcinoma are not clearly defined. The role of thrombophilic genetic factors is well established in other venous thrombotic diseases, as well as in noncirrhotic portal thrombosis. Recently, new, inherited thrombophilic disorders (factor V Leiden [FVL], mutation G20210A of prothrombin [PTHR A(20210)], and mutation TT677 of methylenetetrahydrofolate reductase [MTHFR C677-->T]) have been identified and associated with increased risk of venous thrombosis. The aim of our study was to investigate the role of these thrombophilic disorders in the pathogenesis of PVT in cirrhotic patients. Twenty-three cirrhotic patients with PVT and 40 cirrhotics without PVT were included. A group of 184 patients with deep vein thrombosis (DVT) and 431 healthy persons served as controls. The FVL, PTHR A(20210), and MTHFR C(677)-->T genotypes were identified by a polymerase chain reaction and restriction analysis. The frequencies of FVL, PTHR A(20210) mutation, and homozygous MTHFR C(677)-->T were 13%, 34.8%, and 43.5% in cirrhotic patients with PVT and 7.5%, 2.5%, and 5% in cirrhotic patients without PVT, respectively. Five patients in the former group had associated defects. A thrombophilic genotype was detected in 69.5% of the patients with PVT. Identification of this high-risk group may have implications in patients who are candidates for major surgery or liver transplantation, and may influence the duration of oral anticoagulation.
The pathogenesis of antiphospholipid antibody (aPL) related thrombosis is multifactorial and includes, amongst others, enhanced coagulation activation measured as prothrombin fragment 1 + 2 (F1 + 2), elevated plasma levels of von Willebrand factor (vWF), plasminogen activator inhibitor (PAI) and endothelin-1 (ET-1) as well as heightened thromboxane generation and lipid peroxidation. To evaluate the antioxidant susceptibility of some of the above pathways, probucol (500 mg/d orally, a cholesterol lowering agent bearing antioxidant properties) was administered for a three week period to 14 subjects with aPL and to seven healthy controls. At baseline aPL participants showed higher plasma levels of vWF (P = 0.006), ET-1 (P = 0.0002) and enhanced urinary excretion of 11-dehydro-thromboxane-B2 (TXB2) (P = 0.0004), F2-isoprostanes (marker of lipid peroxidation) (P = 0.02) and albumin (P = 0.04) than controls. In the aPL group baseline IgG anticardiolipin (aCL) titre positively related with urinary TXB2 (r2 = 0.43, P = 0.01) and inversely with urinary NOx (r2 = -0.6, P = 0.005) whereas urinary NOx and TXB2 were negatively correlated (r2 = -0.42, P = 0.01). After the treatment period significant decreases from baseline values were noted for PAI (P = 0.01), ET-1 (P = 0.006), TXB2 (P = 0.02), F2-isoprostanes (P = 0.01) and albuminuria (P = 0.01) in aPL participants but not in controls. These pilot data support oxidative sensitive mechanisms and a potential role for antioxidant treatment in the pathogenesis of aPL induced vasculopathy.
STUDY OBJECTIVES: To investigate whether the FII A(20210) mutation is associated with isolated pulmonary embolism (PE). DESIGN: Case-control study. SETTING: Five thrombosis centers in southern Italy. PATIENTS: Six hundred forty-seven consecutive referred patients with objectively documented venous thrombosis and 1,329 control subjects. MEASUREMENTS AND RESULTS: Medical histories were collected. The G-to-A transition at nucleotide 1691 within the factor V gene (FV Leiden) and the G-to-A transition at nucleotide position 20210 within the prothrombin gene locus (FII A(20210)), levels of anticoagulant factors, and levels of antiphospholipid antibodies were determined by standard techniques. Patients with deep venous thrombosis (DVT) of the lower extremities (n = 346) or with additional PEs (n = 175) showed similar prevalences of FV Leiden mutation (24.3% and 16.6%, respectively) and FII A(20210) mutation (14.2% and 12.6%, respectively), and similar deficiencies of natural anticoagulants (4.9% and 2.3%, respectively). In both groups, the frequencies of FV Leiden and/or FII A(20210) mutation were higher than those observed among 1,329 apparently healthy control subjects (4.8% and 4.4%, respectively; p < 0.0001). Among patients with isolated PE (n = 126), prevalences of FV Leiden (7.1%) and FII A(20210) mutation (8.7%) were similar to those of control subjects. Inherited thrombophilic abnormalities were less frequent among patients with PE only (15.6%) than among those with DVT only (37.0%; p < 0.001) or whose conditions were complicated by PE (28. 0%; p = 0.020). Adjusting for age and sex, FV Leiden mutation, FII A(20210) mutation, or both mutations were associated with DVT with PE (FV Leiden mutation: odds ratio [OR], 3.0; 95% confidence interval [CI], 1.6 to 5.5; FII A(20210) mutation: OR, 2.6; 95% CI, 1. 3 to 5.2; and both mutations: OR, 82.1; 95% CI, 7.5 to 901.2) or without PE (FV Leiden mutation: OR, 6.1; 95% CI, 4.0 to 9.3; FII A(20210) mutation: OR, 2.8; 95% CI, 1.7 to 4.8; and both mutations: OR, 167.5; 95% CI, 21.6 to 1,297.7), but not with isolated PE (FV Leiden mutation: OR, 1.2; 95% CI, 0.5 to 2.8; FII A(20210) mutation: OR, 1.2; 95% CI, 0.5 to 3.1; and both mutations: OR, 22.1; 95% CI, 1. 3 to 370.2). CONCLUSIONS: FII A(20210) mutation is associated with DVT in the lower extremities alone or when complicated by PE, but it is not associated with isolated PE.
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Cytochrome P450 CYP2C9 gene variants have been associated with hyperresponsiveness to small doses of warfarin and a higher bleeding complication rate. The aim of this study was to investigate whether CYP2C9 gene variants affect doses of drug prescribed to acquire the target anticoagulation intensity and the occurence of bleeding complications. In a cohort of 180 patients followed up at one specialized clinic from the start of the anticoagulation with warfarin, we have investigated whether CYP2C9 gene variants have affected doses of drug prescribed to acquire the target anticoagulation intensity and the incidence of bleeding complications. The adjusted dose required of warfarin was higher among patients with the CYP2C9*1 haplotype (5.6 mg) than those of patients carrying the CYP2C9*2 (4.7 mg; p = 0.007, Scheffé's test) or the CYP2C9*3 haplotype (4.0 mg; p <0.001, Scheffé's test). The occurrence of bleeding complications was more frequent among patients with the CYP2C9*2 and/or the CYP2C9*3 haplotype than in carriers of the CYP2C9*1 haplotype (OR: 2.57; 95% CI; 1.16-5.73). An interaction between the presence of local bleeding sources and the CYP2C9*2 and/or the CYP2C9*3 haplotype was observed (p <0.001). Patients with both local sites of potential bleeding and CYP2C9*2 and/or the CYP2C9*3 haplotype had the higher estimated risk of bleeding (OR: 12.81; 95% CI: 2.86-57.26). CYP2C9 gene variants modulate the anticoagulant effect of the dose of warfarin prescribed. The incidence of bleeding complications in CYP2C9*2 and CYP2C9*3 carriers was significantly higher than that in noncarriers and interacted with the presence of local bleeding sources.
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At a young age, ischemic stroke is an uncommon event in which prothrombotic factors are likely to play an important role. In 202 referred cases, 105 men and 97 women, median age 39 years (range, 3 to 50), with a history of ischemic stroke and in 1036 age frequency-matched apparently healthy individuals from the same ethnic background, we have investigated whether inherited prothrombotic conditions increase the risk of ischemic stroke. Neither abnormal plasma levels of natural anticoagulants and fibrinogen nor significant increase of the prothrombin A20210 allele was found in stroke cases compared with controls. Hypertension (odds ratio [OR], 22.61), male sex (OR, 2.30), smoking (OR, 2.78) and alcohol habits (OR, 0.14), a personal history of venous thromboembolism (OR, 4.53), a family history of stroke (OR, 1.93), high circulating levels of fibrinogen (P=0.0190), and total cholesterol (P=0.101) were all independently associated with ischemic stroke. Compared with noncarriers, carriers of the factor V (FV) Leiden mutation (OR, 2.56), and to a lesser extent, of the methylenetetrahydrofolate reductase (MTHFR) TT genotype (OR, 1.60), had an independent higher estimated risk of having a history of ischemic stroke. The relationship with the FV Leiden mutation was greater in women (OR, 3.95). Thus, in addition to established determinants, FV Leiden mutation is independently associated with the occurrence of ischemic stroke in this setting. The greater association in women suggests the possibility of an interaction of this genotype with female hormones.
Giant platelets in the blood smear, absent in vitro platelet agglutination in response to ristocetin, and normal aggregation, ATP secretion and thromboxane B2 formation were found in a young patient with a life-long bleeding tendency. Ristocetin-induced von Willebrand factor binding to her platelets was less than 10% of normal. Flow cytometric analysis with monoclonal antibodies LJ-Ib-1, LJ-Ib-10, and LJ-P3 was consistent with the latter finding. SDS-PAGE analysis of solubilized platelets showed a marked reduction of the platelet glycoprotein (GP) Ibalpha. Genetic characterisation demonstrated that the patient and her father were heterozygous for a deletion of 36 nucleotides (positions 554-589) leading to a mutant GPIalpha (deletion of aminoacids from residue 169 to 180 and a Glu --> Lys substitution at residue 181). In addition, a C --> T transition at nucleotide 515 in the other allele of the GPIbalpha gene was found in the patient and in her mother that results in the substitution of alanine for valine in codon 156 (Bernard-Soulier type Bolzano). These variations occurred within the VI and VII leucine-rich repeats. The novel variant of Bernard-Soulier syndrome identified further suggests that the integrity of leucine-rich repeats is important for normal function of the GP Ib-IX-V receptor complex.
Patients carrying the FV Leiden or the FII A20210 mutation have a high risk of venous thromboembolism. Among 542 patients with a documented diagnosis of deep venous thrombosis in one leg consecutively referred for a thrombophilic work-up, we have retrospectively assessed the rate of objectively documented previous recurrence in carriers of both FV Leiden and FII A20210 mutations. Eighty-two patients had experienced 115 episodes of recurrent venous thromboembolism. The rate of recurrent venous thromboembolism was 29.2% among subjects with and 14.5% in those without deficiencies of natural anticoagulant proteins (p = 0.055), and 24.6% among patients with and 14.0% in those without antiphospholipid antibodies (p = 0.036). The frequency of having a recurrent thromboembolism was 16.2%, 20.0%, and 36.4% among carriers of FV Leiden, FII A20210 mutation, or both gene defects, respectively, and 12.8% in subjects carrying neither mutation (p for trend = 0.004). When adjusted for age, sex, and thrombophilic risk factors, the rate was higher among patients with than in those without deficiencies of natural anticoagulant proteins (OR: 3.0; 95% CI: 1.2-7.5), aPL 2.5 (95% CI: 1.3-4.9), or both FV Leiden and FII A20210 gene mutations (OR 4.8; 95% CI: 1.9-12.2). The rate of previous recurrent venous thromboembolism was significantly higher in subjects carrying both FV Leiden and FII 20210 mutations and was comparable to that observed in subjects with deficiencies of natural anticoagulant proteins or antiphospholipid antibodies.
BACKGROUND: A mutation in the prothrombin gene (G-->A20210) has been associated with higher plasma prothrombin levels and an increased tendency for venous thrombosis. OBJECTIVE: To determine whether the prothrombin A20210 allele is independently associated with the occurrence of venous thrombosis. DESIGN: Case-control study. SETTING: Two thrombosis centers in southern Italy. PATIENTS: 281 consecutive patients with venous thrombosis confirmed by objective tests and 850 controls. MEASUREMENTS: Medical history was collected on standardized questionnaires. The presence of prothrombin G-->A2020 and factor V Leiden mutations was determined by polymerase chain reaction. The presence of anticoagulant factors and prothrombin activity was determined by tests of function. RESULTS: In 150 controls, increased prothrombin activity (P < 0.001) was associated with the prothrombin A20210 allele. This allele was more frequent in patients than in controls (8.01% compared with 2.29%; P < 0.001) and was associated with an increased risk for thrombosis (odds ratio, 3.88 [95% CI, 2.23 to 6.74]). The increased prevalence of this allele was independent of the presence of the factor V Leiden mutation. After adjustment for sex, age, arterial thrombosis, and factor V Leiden mutation, the risk was still significantly elevated (odds ratio, 3.13 [CI, 1.89 to 5.21]). Moreover, the overall prevalence of inherited coagulation abnormalities was significantly higher in patients with thrombosis of the lower extremities than in patients with thrombosis of the upper extremities (odds ratio, 3.77 [CI, 1.10 to 12.93]). Fourteen patients carried both the prothrombin G-->A20210 and factor V Leiden mutations. CONCLUSIONS: The prothrombin A20210 allele is independently associated with the occurrence of venous thrombosis, particularly in patients with a history of thrombosis of the lower extremities.
OBJECTIVE: This study's objective was to evaluate the association between venous thromboembolism during pregnancy and the postpartum period and the factor V Arg 506 Gln (factor V Leiden), the prothrombin G20210A, and methylenetetrahydrofolate reductase C677T polymorphisms. STUDY DESIGN: In this case-control study 42 case patients and 213 control subjects (parous age-matched women without history of thrombosis) were genotyped for all the polymorphisms. Moreover, antiphospholipid antibodies and protein C, protein S, and antithrombin III deficiencies were investigated in each case. RESULTS: Ten case patients (23.8%) and 4 control subjects (1.9%; odds ratio 16.3, 95% confidence interval 4.8-54.9) carried the factor V Leiden mutation; 13 case patients (31.0%) and 9 control subjects (4.2%; odds ratio 10.2, 95% confidence interval 4.0-25.9) were carriers of the prothrombin G20210A allele. Finally, 12 case patients (28.6%) and 34 control subjects (16.0%; odds ratio 2.1, 95% confidence interval 1.0-4.5) were homozygotes for methylenetetrahydrofolate reductase C677T. Overall, mutations were found in 25 case patients (59.5%) and 47 control patients (22.2%; odds ratio 5.2, 95% confidence interval 4.9-19.6). One patient carried the antithrombin III deficiency and 1 the protein S deficiency, whereas 2 women had a primary antiphospholipid syndrome. CONCLUSIONS: The significant risk estimates of having a pregnancy-related venous thromboembolism in the presence of the prothrombotic genetic risk factors analyzed suggest to screen for these mutations women with a personal history of thromboembolic events during pregnancy or the postpartum period.
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To evaluate the significance of common thrombophilic genotypes in subjects with idiopathic antiphospholipid antibodies (aPL) we determined the methylenetetrahydrofolate reductase C677-->T (MTHFR) and factor V A506-->G (FV Leiden) polymorphisms in 49 subjects with idiopathic aPL (57% of whom suffered spontaneous vein thrombosis), in 70 subjects with a history of spontaneous vein thrombosis and in 193 healthy subjects. The prevalence of MTHFR C677-->T+/+ (homozygotes) was 25%, 18% and 17% respectively amongst aPL thrombotics, non aPL thrombotics and controls and that of MTHFR C677-->T+/- (heterozygotes) was 53%, 59% and 53% respectively in the same groups. The prevalence of FV Leiden was higher in aPL thrombotics (14%) and in non aPL thrombotics (18%) than in controls (4%) (p < or = 0.05). APL thrombotics with MTHFR C677-->T+/+ had a lower mean age at first thrombotic event (22 +/- 6 years) than aPL thrombotics with MTHFR C677-->T+/- and non mutated considered together (38 +/- 14 years, p = 0.0004) and than non aPL thrombotics with MTHFR C677-->T+/+ (38 +/- 14 years, p = 0.003). FV Leiden may contribute to the hypercoagulability of a small, albeit significant proportion of thrombotic aPL subjects, whereas the association between MTHFR C677-->T+/+ and aPL may have an impact on age at first occlusive event and suggests a possible pathogenetic interaction.
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A polymorphism, C-->T677, in the methylenetetrahydrofolate reductase (MTHFR) gene has been identified as a cause of mild hyperhomocysteinemia, a risk factor for venous thrombosis. We have investigated the frequency of the TT genotype in 277 consecutive patients with confirmed deep venous thrombosis and 431 healthy subjects. The TT MTHFR genotype was more frequent in patients than in controls (25.6% vs. 18.1%; p = 0.016). The risk of thrombosis among carriers of this genotype was significantly increased [odds ratio: 1.6 (95% CI: 1.1-2.3)]. The estimated risk associated with the TT genotype was 2.0 (95% CI: 1.3-3.1) in subjects with (n = 122), and 1.3 (95% CI: 0.8-2.0) in those without (n = 155) predisposing (hereditary, acquired or circumstantial) risk factors for venous thrombosis. Factor V Leiden and prothrombin G-->A20210 are known risk factors for venous thrombosis. After stratification for FV Leiden and prothrombin A20210 mutations, a significant association was also observed. After adjustment for sex, FV Leiden and prothrombin A20210 mutation, the estimated risk of venous thrombosis among carriers of the TT MTHFR genotype was 1.7 (95% CI: 1.2-2.6). The TT MTHFR genotype is independently associated with venous thrombosis, mainly among individuals with a high risk profile.
The relationship between anticardiolipin antibodies (aCL) and acute myocardial infarction (AMI) is still controversial. The purpose of this study was to investigate the prevalence of aCL in young patients (age < or = 45 years) with AMI; record the aCL titre during different days of disease; assess the relationship between aCL titres and in-hospital myocardial infarction complications. The aCL were measured in 108 consecutive patients and in 31 controls (ELISA method). High aCL levels (IgG or IgM) were found in 19/108 (17.6%) patients and 5/31 (16.1%) controls (NS); aCL titres were similar in different days after AMI and did not differ in controls and in patients with or without early myocardial infarction complications. In conclusion, the aCL levels are not elevated in AMI patients, do not change during the early stage of the disease and are not associated with in-hospital complications.
Systemic sclerosis (SSc) is a disease characterized by progressive microvascular occlusion and fibrosis resulting in irreversible organ damage, the pathogenesis of which is felt to be of vascular origin. To gain a comprehensive view of the coagulation/fibrinolytic balance in SSc, a number of haemostatic and fibrinolytic variables were measured in 26 SSc patients (11 limited, 15 diffuse) and in 22 control subjects. Of the coagulation activation markers, the mean plasma level of prothrombin fragment 1 + 2 (F1 + 2), but not of thrombin-antithrombin complexes (TAT), was higher in SSc patients than in controls (P < 0.001). Plasma levels of fibrin split product D-dimer (DD), fibrinogen (FNG) and von Willebrand factor (vWF) were higher amongst patients than controls (P < 0.001). vWF and FNG levels were positively correlated (P < 0.001). Mean levels of DD and vWF were more elevated in patients with diffuse than limited disease (P = 0.001 and P = 0.04, respectively). On the fibrinolytic side, defective tissue plasminogen activator (tPA) release (venous occlusion test, stimulated level < basal level) was noted in 46% (12/26) of SSc patients, but only in 4% (1/22) of controls. Patients had higher mean levels of tPA inhibitor (PAI) than controls (P < 0.001), levels being more elevated amongst patients with diffuse than limited disease (P = 0.01). An abnormally high lipoprotein (a) [Lp(a)] level was found in 9% (2/20) of control subjects, but in 30% (8/26) of SSc patients (P = 0.04) where it clustered with fibrinolytic defects. Altogether, these data suggest that patients with SSc are in a hypercoagulable state characterized by elevated plasma levels of FNG and vWF, by a dual hypofibrinolytic pattern (defective tPA release and elevated PAI), and by increased thrombin generation with enhanced fibrin formation. Higher levels of vWF, DD and PAI in patients with diffuse disease are consistent with more extensive (micro)vascular involvement, although no causal relationship can be inferred. The lack of a parallel increase of TAT with F1 + 2, in the presence of normal levels of antithrombin III (ATIII), indirectly suggests an impairment of the heparan sulphate-ATIII system which would favour thrombin generation. Since thrombin may act as a mitogen for fibroblasts, may upregulate vWF, PAI and endothelin production by endothelial cells, and may promote fibrin deposition on the vessel wall leading to worsening of microvascular occlusions, limitation of thrombin generation, besides fibrinolytic enhancement, could represent a possible coadjuvant interventional strategy.